It has been conjectured that, close to a spacelike singularity, the classical dynamics of any universe
follows a chaotic behavior given by the Belinski-Khalatnikov-Lifshitz (BKL) scenario [1]}.
According to this,
different points decouple and the dynamics of each point can be described by
a Bianchi IX universe, which is characterized by an alternation of different Kasner epochs
(corresponding to a Bianchi I vacuum or Kasner solution) connected by quick transitions
(as compared with the duration of the epochs). The alternation among epochs implies that different (anisotropic) spatial
directions are squeezed and stretched during the evolution towards the singularity, resulting in the mentioned chaotic behavior.
One relevant characteristic of this conjecture is that this behavior is dominated by the vacuum solution, and the introduction
of matter (besides particular cases) does not change the qualitative behavior.
